Mark making tools become an obsession after awhile. It's fascinating to try all KINDS of pens. This is a Loew Cornell Fine Line "Paint" pen. It is designed to hold any thin liquid. I am trying out Hydrus Watercolors here (pre-mixed liquid Dr. Martin brand).
The barrel at the top is gently filled with the liquid (I use a small paint brush as the filling tool because it helps keep any bubbles from forming. You can also dip it fully into a liquid but then you have a lot of wiping to do. So I prefer the paint brush. You don't get a huge amount of printing before having to refill, of course. That is a downside to this.
It is definitely a "studio" printing technique end not designed to be carried about for use. I have used liquid acrylic paint in this and this works nicely too and would provide more opaque lettering that you could wash over. And the white works nicely over black backgrounds too. I like that you can use a huge variety of colors and paints with it...not just your normal black, white, and blue.
It's important to wash and clean immediately after use, of course, so the tiny nozzle won't get clogged and it does come with a tiny wire you can use in case this happens. You can also blow through it to clean it out after it is washed in clean water. So it has some housekeeping issues. But I rather like it. The marks are easy to make...liquids flow so nicely that the pen just glides over smooth paper.
Has anyone else tried one of these? It is not expensive.